1. Field of the Invention
The present invention relates to a humidification unit, a humidifying unit for an artificial respiratory device, and a method for manufacturing of a humidification unit.
2. Description of the Related Art
Japanese Patent Application Unexamined Publication No. 62-26, 076 discloses a humidification unit that uses a gas permeable tube having a peripheral wall with minute openings defined in the wall. The openings are large enough to allow water vapor to permeate through the peripheral wall yet small enough to prevent water from passing therethrough. More specifically, this humidification unit includes a gas permeable tube having a peripheral wall with minute openings that are arranged in such a way that an electrically exothermic member having an inner diameter of at least 3 mm or larger is disposed in this single gas permeable tube. During use, the gas permeable tube communicates with a water supply source and is filled in with water. Water vapors are discharged from the gas permeable tube through the minute openings provided in the peripheral wall with the aid of heat generated from the electrically exothermic member.
The humidification unit described above, however, has a disadvantage in that should the gas permeable tube break, an unacceptably large amount of water is likely to leak outside the tube. For example, in the case where such a humidification unit is employed in a patient circuit for an artificial respiratory device, a large quantity of leaking water from the gas permeable tube may become hazardous, especially if the leaked water causes a decrease in the humidifying function or if the leaked water flows into the intake side of the artificial respiratory device, i.e., the side connected to a patient.